Amazon is more valuable than all major brick-and-mortar retailers combined.

The sum total of those investments in infrastructure and supply chain management have made Amazon by far the most valuable retailer in the United States.

Amazon's $356 billion valuation is so big, it's larger than Wal-Mart, Target, Best Buy, Macy's, Kohl's, JCPenney, and Sears combined.

With the recent acquisition of Whole Foods, there are no signs the retailer has any plans of slowing down.